New concepts in public transportation include the use of linear induction motors (LIMS) for propelling individual cars of a train. LIMS can be used for propelling the cars and/or for levirating them.
A basic explanation of the operation of an LIM is provided in the detailed description below. Efficient propulsion by an LIM requires that associated propulsion coils be maintained in very close proximity to a reaction track without touching it. Other complications arise from track undulations and the need to elevate the propulsion coils away from the track to avoid damage from debris and track surface anomalies. All of this must be accomplished with a system which is immune from electromagnetic interference otherwise resulting from operation of the propulsion coils.
An object of the invention is to provide a pneumatic and fluidic sensing system which will meet the proximity sensing requirements of LIM cars while avoiding electromagnetic interference. Other objects and advantages of the invention may become apparent from the following descrition, which includes the appended claims and accompanying drawings.